Process for preparing oxonol dyes



Patented Dec. 12, 195:0

2,533,206 PROCESS :Foc 4r1melamine oxoNoLDyEs' Samuel G. Dent, Jr., and`LeslieY G.- S. Brooker,` Rochester, N. X., assignors `to Eastman Kodak-;Gomnany, loehesier, N. Yi, a comorationof New Jersey No-Drawing.Applieetionlebruary .251., 1.949;

' serialnavspsfi (Cl. E60-12ML?) leims 1 This invention relates .to aprocess for preparing oxonol dyesand to new dyes obtainable thereby.

4It is well known that ,certain pyrazolone oXonol dyes can 4be preparedby `condensing `a pyrazolone compound with `an ortho ester. For example,a dye of the following formula: I /'N\ N\ cuni-N o-orn CH3-o" N-cm,

has been prepared Iby condensing two molecular proportionsv of3-methyl-l-phenyl--pyrazolone with one molecular `proportion of ethylorthoformate (Claisen-.Annalen der Chemie, vol. 297 (1897), p. 37).

The synthesis of Claisen is limited in its applicability, however, since2-thio-2,f1v(3,5)thi azoledones (rhodanines), 2-thio-2,4 3,5)oxazolediones and 2.thio-2,4 3,5) -imidazolediones (2-thiohydantoins)cannot be condensed with esters of orthoformic acid, such as ethylorthoformate, rto give .oxonol dyes. In Brooker land Keyes ,U.:S.\;Patent 2,241,238, dated l.May 6, 1941, one :method for :preparingthese heretofore 1un- Iattainable dyes is described.

`:We have now found .that the dyerepresentedby Formula1, and a largenumber of v:dyes which cannotbe prepared bythe ortho ester method .ofClaisen, can be prepared by still another method which ,comprisescondensing .an organic compound containing a reactive Vmethylene group`adjacent to a carbonyl group With adialkoxymethyl carboxylate (e. g.diethoxymethyl acetate, etc.).

It is, accordinglyan object .of -this invention to provide a processfor-preparing -oxonol dyes. Another object. is to provide new oxonoldyes, some of which areuseful in sensitizing photographic silver-halideemulsions and some of which are useful in the preparation ofoVerco-ating layers, lter and antihalation layers. A still furtherobject is Vto `providephotographic emulsions and photographic elements(lter-glayers, antihalation layersfetc.) containing-these new dyes.Other objects will become `apparentfronl a consideration of -thefollowing examples and description.

kIn accordance With our invention, we `condense an organic compoundcontaining a reactive methylene group adjacent to a carbonyl group (i.e. an organic compound containing a -CHz--CO- group) with adialkoxymethyl .carboxylate (e. g. `diethoxymethyl acetate, etc).

As organic ,compounds .containing a reactive methylene group,thoserepresented :by the following two general `fiiormulasican be used:

wherein .repeesenisememberselected from ,the eoupfeonsistin.oeranoefouaeoerboxylsroup, ecerbelkoxylv-sr. ,o Kee-e .eerieemeihes/l.oeuf# beweer-,1 eiesrouu.,fee'eeyleroupoi .e eeeoxylie acid u(e.,g.'acetylhgpropionyl, etc. .g ups) acarbar. ruyl `eroico endeheieroeyolie mieleus of tueuuiuf Oli-Deseriesegee .2.-1'Orf4vquinolylgroup) @gen1` resents sfmember seleeiedfromthesrouo .eene Sistine of@hydroxyl greep en .alkyl group Ke-- ruethlvl, ethyl, ete-erwies) .arylgroup '.(eee `plfleuyl group. .emoolio-bowl group. ete). ainioo .group(ete.. .e .-NHs group, en euiliuo group, ete-l, .e .esrbalkeyl-sroup les .l-terloo-l methosyl., earbeihozyl. eto- .groupsh elkoigyl group Lie.g.me.thoxy1,.ethoylnetcgroups) and e heteroerolie .nucleus of the-beuzefur'yl serie; (e. e v.s hemofurylggroup, etc.) end represents the.non-.metallic siomslueeessery to complete e nucleus selected from thegroup Ieolfisisiirig of .e heterocyclic .nucleus containing "from `5 Ato4 f atoms .in theheieroorelie .lingerie .e eelheeyelie nucleus.containing 5 .atoms Il the ring le.` e. en indaudiorie .uueleu.s.Especially .edreeieeeeus are `e02.11.1f1ounf1s `..1feorefseuied ,by.Formule 1.11 wherein'z rerzieseuts .the ooo-metallic ,stores necessary.to oomplete ,e heieroeyelie uuleus harias from ..5 .to .6 -stoms theheierooscle ring. Typical of the nuclei represented 'by Formule E111.ere those .of the ihiezoloue Series for example: those of thej2,4(-3;5)thiazole 2,4(3,5) -thiazoledione (3-(1benzothiazy1)rhodanine), etc., those of the 2-a1ky1mercapto-4(5) thiazolone series, suchas 2-ethy1mercapto-4(5)- thiazolone, etc., those of the thiazolidoneseries, such as 4-thiazolidone or its 3alky1 (e. g. ethyl, etc.)S-phenyl or 3-a-naphthyl derivatives, those of the2alkylphenylamino-4(5) -thiazolone series (e. g. 2-ethylphenylamino-4(5)thiazo1one, etc.), those of the 2diphenylamino-4(5)-thiazolone series;those of the oxazolone series, for example: those of the2-thio-2,4(3,5)-oxazolidione series, such as3-alkyl2-thio2,4(3,5)-oxazolidiones (e. g. 3 ethyl 2 thio 2,4(3,5)oxazolidone, etc.), those of the 2-imino2,4(3,5)-oxazolone(pseudohydantoin) series, etc.; those of the imidazolone series, forexample: those of the 2,4(3,5)imidazo1edione series, such as 2,4(3,5)imidazoledione (hydantoin) or its S-alkyl (e. g. ethyl, etc.), S-phenylor S-a-naphthyl derivatives as well as its 1,3-dialkyl (e. g.1,3-diethyl, etc.), 1-alkyl-3-phenyl (e. g. 1-ethy1-3-phenyl, etc.),I-alkyl-S-naphthyl (e. g. 1ethyl3anaphthyl, etc.), 1,3-diphenyl, etc.derivatives, those of the 2-thio2,4(3,5) -imidazoledione series, such as2- thio-2,4(3,5) -imidazoledione (2-thiohydantoin) or its 3-a1kyl (e. g.3-ethyl, etc.), B-phenyl or 3- a-naphthyl derivatives as well as its1,3-dialkyl (e. g. 1,3-dethy1, etc.), 1-alkyl-3-phenyl (e. g. 1-ethyl-S-phenyl, etc.) l-'alkyl-B-naphthyl (e. g. 1- ethyl-S-a-naphthyl),1,3-diphenyl, etc. derivatives, those of the2alkylmercapto-5(4)-imidazolone series, such as 2-n-propylmercapto-5(4)imidazolone; those of the thionaphthenone series, such as2(1)-thionaphthenone or 1(2)-thionaphthenone; those of the pyrazoloneseries, such as pyrazolone or its l-alkyl (e. g. methyl, ethyl, etc.),l-phenyl, l-naphthyl (e. g. l-anaphthyl), 3-alkyl (e. g. methyl, ethyl,etc.), 3- phenyl, -naphthyl (S-a-naphthyl), 1-alkyl-3- phenyl (e. g.1-methyl-3-phenyl, etc.), 3-alkyl-1- phenyl (e. g. 3-methyl-1-phenyl,etc.), 1,3-dialkyl (e. g. 1,3-dimethyl, etc.), 1,3-diphenyl, etc.derivatives; those of the oXindole series, such as2,3-dihydro-3-ketoindole, and like ve-membered heterocyclic nuclei;those of the 2,4,6-triketohexahydroseries, for example, 2,4,6,-triketohexahydropyrimidine (barbituric acid), 2-thio-2,4,6triketohexahydropyrimidine (Z-thiobarbituric acid) as well as theirl-alkyl (e. g. l-ethyl, etc.) or 1,3-dialkyl (1,3-diethyl, etc.)derivatives; those of the 3,4-dihydro-2(1)-quinolone series, such as3,4-dihydro-2(1)-quinolone (dihydrocarbostyril); those of the3,4-dihydro2(l) quinoxalone series, such as 3,4-dihydro2(l) quinoxalone(oxydihydroquinoxaline), etc.; those of the 3-phenomorpholone(1,4,3-benzoxazine- 3(4)-one or benzo--morpholone) series, such as-phenomorpholone, etc.; those of the 1,4,2- benzothiazine 3(4) one(ketodihydrobenzoparathiazine) series, such asketodihydrobenzoparathiazine, etc., and like six-membered heterocyclicnuclei. The compounds of Formula III wherein Z represents thenon-metallic atoms necessary to complete a live-membered heterocyclicnucleus containing a nuclear nitrogen and a nuclear thiocarbonyl groupgive rise to dyes which provide emulsions of particular utility. Thosecompounds of Formula III wherein Z represents the non-metallic atomsnecessary to complete a siX-membered heterocyclic nucleus containing twonuclear nitrogen atoms and a nuclear thiocarbonyl group also providedyes which are excellently adapted for the manufacture of photographicsilver halide emulsions.

The dialkoxymethyl carboxylates advanta- IV R10 wherein R, R1 and R2each represents an alkyl group, such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, etc. groups (e. g. an alkyl group havingthe formula CnHznJfi wherein n represents a positive integer from l to4). rIhe esters represented by Formula IV can advantageously be preparedby reacting an ortho ester (e. g. triethyl orthoformata'etc.) with acarboxylic acid anhydride (e. g. acetic anhydride, etc). Such a methodis described by I-I. W. Post in Jour. Organ. Chem, vol. 2 1937), pp.260-266. Diethoxyrnethyl acetate has been found to be especially usefulin practicing our invention, although other esters, e. g. diethoxymethylpropionate, etc. can be used.

The condensations of our invention can be carried out in the presence orabsence of a solvent or diluent. As solvents or diluents, we can use thetertiary amines, e. g. triethylamine, tri-nbutylarnine, pyridine, etc.,carboxylic acid anhydrides (e. g. acetic anhydride, etc.), cyclic ethers(e. g. 1,4-dioxane), piperidine, acetic acid, formamide, nitromethane,nitrobenzene, cresols, etc. The condensations are accelerated by heat,and generally, it is advantageous to subject the reactants totemperatures above room temperature.

The following examples will serve to illustrate more fully the mannerwhereby we practice the process of our invention.

A mixture of 6.4 Ve.' (2 m01.) of 3-ethy1- rhodanine, 3.2 g. (1 mol.) ofdiethoxymethyl acetate and 5 cc. of triethylamine Was heated at thetemperature of a steam bath for 3() minutes,

, cooled, and poured with stirring into 200 cc. of

ice-cold diet-hyl ether. The solid dye which separated was collected ona funnel, washed With more ether, and dried. The yield of dye Was 46%crude and 29% after recrystallization from ethyl alcohol (l0 cc./g. or"dye). The triethylamine salt of the dye melted at about 178 C., and gavea bluish-red solution in methyl alcohol.

Example 2.-Bis(benzoylacetonitrile) methinoxonol CN N atea-208 two such-recrystallizations, `the ldye =meltediat 'about 238 C.

A solution of 8.8 g. (2 mol.) of 3ethyl-1 phenyl-Z-thiohydantoin and`3.2g. (1 mol.) of diethoxymethyl acetate in ce. of piperidne was heated bymeans of an oil bath to 120 C. for 17 hours. After cooling to roomtemperature, the dark viscous product was poured with stirringlintoBOOcc. of water containing 10-c'c. of acetic acid. lThe viscous brown oilwhich precipitated was separated by decanting the aqueous layer, and theoil was washed with stirring `with three portions of water. The oilyproduct was then dissolved in hot ethyl alcohol, about by Volume ofwater was added along With enough acetic acid to make the solutonslightly acidic. After chilling, a pinkish-White solid was collected onthe funneLmwashed with a littlevdiethyl ether and dried. The yield ofdye 'was 56% crude and 14% after two recrystallizations from'ethylalcohol `(250 cc./g. of dye). The dye melted at about 203 C. andrgave ayellow solution in methyl alcohol.

Example 4 Bisr1 ethyzomdoze (snimeth- A solution of 6.4 g. (2 mol.) ofl-ethyloxindole and 3.2 g. (1 mol.) of diethoxymethyl acetate in 10 cc.of piperidinewas-heated at 120 C. for 17 hours by means of an oil bath.After cooling, the amber-colored oily mixture was poured Withstirringinto 300 cc. "of water made slightly acidic with acetic acid. The orangeoil was washed twice'with water and then stirred with ethyl alcohol,whereupon a red crystalline solid separated. The yield of dye was 17%crude and 12% after two recrystallizations from ethyl a1- cohol (300cc./g. of dye). The dye (acid) melted at about 184 C. and gave a yellowsolution in nl'ethyl` alcohol.

Example y5.--Bz'sl2 diphenylamino 4(5)l e thiazolone (5) lmethznoxonolpyridine salt A mixture of 5.36 g. (2 mol.) of2-diphenylamino-4(5)thiazolone and 1.62 g. (1 mol.) of diethoxymethylacetate in 10 cc. of piperidine was heated at 120 C. for one hour bymeans of an'oil bath. The reddish reaction product was cooled to roomtemperature and poured with stirring into 800` cc.- of cold wateruwhichhad Ueriia'cidiediwith acetic acid. The oily prodtions of water and thendissolvedin cc.'of hot ethyl alcohol. lThe red solid which crystallizedout upon cooling the alcohol solution was collected on a 1funnel, washedwith a littlediethyl ether and '-dried. The yield of dye was `11% crudeand" 6% after two recrystallizations from a pyridineeethyl alcoholmixture. The pyridine salt of vthe dye melted at about 258 C. andvitssolution in methyl alcohol was pink.

8.7 g. (2 mol.) "of 3-methyl-1-phenyl-5-pyrazolone and 8 g. (1`mol. -4-100% excess) of diethoxymethyl acetate were mixed in a 50 cc.'laskfitted' with a short, wide tube and a thermometer. The "temperature ofthe reaction mixture was raised slowly by means of a heating mantle toC., at which point the reaction mixture began to boil. While thelow-boiling vapor which was evolved was allowed to escape, thetemperature of the reaction mixture was slowly raised overa period ofone hour to 133 C., at which'point the evolution of the vapor valmostceased. The hot reaction mixture then 'was poured'with stirring into250i cc. of hot ethyl alcohol, "whereupon Aorange-yellow needlesseparated 'from the hot mixture. After chilling, the'solldswere'collected on afunnel,"washed with ethyl alcohol and dried.Theyield of crude dye was 8.8 g. (98%), and after recrystallization fromacetic acid (10 cc./g. of dye), an 84% yield of pure dye melting atabout 182 C. was obtained.

Operating in a manner similar to that set forth in the above examples,other organic compounds containing a reactive Ymethylene grouprepresented by Formulas II and III above can be reacted with adialkoxymethyl carboxylate represented by Formma Iv above.

`Some bfthe dyes prepared in accordance'with the process oourinventionare useful in altering the sensitivity of photographic silver-halideemulsions. Such dyes include those prepared from the compoundsrepresented by Formula III above, for example," wherein "Z representsthe non-metallic atoms necessary to'cc'mplete a heterocyclicnuclouscontaining anuolear nitrogen atom and a nuclear thiocaibonyl* group(particularly a rhodanine, a thiohydantein or a 2-thi02,4(3,5)-oxazoledione nucleus). The freedyes are vsometimesinu'ch strongersensitizersof photographic emulsions than the dye-salts.

4InA 'the preparation 'of photographic 'emulsions containing such dyes;it is only necessary to dispersethe dyes in the emulsions. It isconvenient to add thedyes tothe emulsions in the form'cf solutions inappropriate solvents. The solvent must,` of course, be compatible "withthe emulsion, substantially free 'from any deleterious effect Aon thelight-sensitive materials in the emulsions and capableofv dissolving thedyes. Methanol `is a satisfactory solvent for our dyes. Acetone `'canbe' employed. The dyes are advantageously incorporated inthe finishedwashed emulsions and shouldbe uniformly distributed throughout theemulsions.

The concentration-of ourd-yes in the emulsions egeaaeoe' peri liter ofordinary flowable gelatino-s-lverhalide emulsion. The concentration of.dye will vary according to the type of light-sensitive materialsemployed in the emulsion and according to the effects desired. Thesuitable and most economical concentration for any given emulsion willbe apparent to those skilled in the art, upon making the ordinary'testsand observations customarily emplcyed in the art of emulsion-making. Toprepare a gelatino-silver-halide emulsion, the followingV procedure issatisfactory: A quantity of the dye is dissolved in methyl alcohol oracetone and a volume of this solution (which may be diluted with water)containing from 2 to 1GO mg. of dye is slowly added to 1060 cc. of ai'lowable gelatino-silver-halide emulsion lwith stirring. Stirring iscontinued until the dye is thoroughly incorporated in the emulsion.lOrdinarily from 1f) to 20 mg. of our new dyes per liter of emulsionsuffice to .produce the maximum sensitizing effect.

For the preparation of overcoating layers, filter layers andantihalatiori layers, according to our invention, from 5G ing. to 150mg. of dye are dissolved in from 2 to 5 cc. of a water-miscible solvent.Methanol, or acetone, is suitable for this purpose, but pyridine or-ethoxyethanol can also be used. The solution is then added to about cc.of a 5% gelatin solution at 40 C. and the mixture coated on the support.

What we cla-ini as our invention and desire to be 'secured by LettersPatent of the United States is:

1. A process for preparing a dye comprising condensing an organiccompound containing a lieto-methylene (-Cll.2CO-) group selected fromthe group consisting of those represented by the following two generalformulas:

wherein J represents a member selected from the group consisting of acyano group, a carboxyl group, a carbalkoxyl group, an acyl group of acarboxylic acid, a carbamyl group and a heterocyclic nucleus ofV thequinoline series, Q represents a member selected from the groupconsisting of a hydroxyl group, an alkyl group, an aryl group, acarbalkoxyl group, an alkoxyl group and a heterocyclic nucleus of thebenzofuryl series and Z represents the non-metallic atoms necessary tocomplete a heterocyclic nucleus selected from those of the2,4(3,5)thiazoledione series, those of the 2thio2,4 3,5) -thiazoledioneseries, those of the -2-alkylmercapto i(5)-thiazolone series, those ofthe thiazolidone series, those of the 2-alkylphenylamino-4(5)-thiazoloneseries, those of the 2-diphenylamino-4 5)-thiazolone series, those ofthe 2-thio2,4(3,5)-oxazoledione series, those of the2-imino2,e(3,5)-oxazolone.

series, those of the 2,4(3,5) -imidazoledione series, those of the2-thio-2,e(3,5) -imidazoledione series, those of the2-alkylmercapto-5(4) -imidazolone series, those of the thionaphthenoneseries, those of the pyrazolone series, those of the oXindole series,those of the 2,4,6-triketohexahydropyrimi dine series, those of the3,4-dihydro2(l)quino lone series, those of the 3,ll-dihydro2 1 quinoxalone series, those of the S-phenomorpholone series and those of the1,4,2benzothiazine3(4) Qllefiewiih ,a delkoxymethyl carboxylate se- 8lected. from` those represented by the following general formula: i Y iR1O\ o cH-o-o-RiI R210 wherein R1, R2 and R3 each represents an alkylgroup of the formula CnH2n+1 wherein n represents a positive integerfrom l to 4.

- 2. A process for preparing a dye comprising condensing an organiccompound containing a ketomethylene v(-CII2-CO-) group selected fromthose represented by the following general formula: r I v /Z` H2-c=owherein Z represents the non-metallic atoms necessary to complete aheterocyclic nucleus of the 2-thio'2,4(3,5)-thiazolidone series with adialkoxymethyl carboxylate selected from those represented by thefollowing general formula:

ketomethylene (-CH2-CO-) group selected from those represented by thefollowing general formula:

l, oH2-C=o wherein Z represents the non-metallic atoms necessary tocomplete a heterocyclic nucleus of the 2-thio2,4(3,5) -thiazolidoneseries with a dialkoxymethyl acetate selected from those represented bythe following general formula:

wherein R1 and R2 each represents an alkyl4 group of the formulaCillian-ti wherein 1L represents a positive integer from 1 to 4. ,v 4. Aprocess for preparing a dye comprising condensing3-ethyl-2-thio-2,4(3,5) -thiazoledione (3-ethylrhodanine) withdiethoxymethyl acetate. A process for preparing a dye comprisingcondensing an organic compound containing a4 ketomethylene (-CHz-CO)group selected from those represented'by the following general formula:

wherein Ri, R2 and R3 each represents an alkyll group of the formulaCallian wherein n repre sents a positive integer from 1 to 4.

6. A process for preparing a dye comprising condensingan organiccompound containing .ag

9 ketomethylene (--CH2-CO) group `selected from those represented by thefollowing general formula:

cHr"c=o wherein Z represents the non-metallic atoms necessary tocomplete a heterocyclic nucleus 0f the 2thio2,4(3,5)-midazoledioneseries with a dialkoxymethyl acetate selected from those represented bythe following general formula;

I wherein R1 and R2 each represents an alkyl group of the formulaCul-121m wherein n represents a positiventeger from 1 to 4.

7. A process for preparing a dye comprising REFERENCES CITED I'hefollowing references are of record in the le of this patent: l

UNITED STATES PATENTS Name Date Gasper Mar.. 3, 1942 Number

1. A PROCESS FOR PREPARING A DYE COMPRISING CONDENSING AN ORGANICCOMPOUND CONTAINING A KETO-METHYLENE (-CH2CO-) GROUP SELECTED FROM THEGROUP CONSISINT OF THOSE REPRESENTED BY THE FOLLOWING TWO GENERALFORMULAS: